Signal output device and signal output method

ABSTRACT

A signal output device includes a signal output unit to output a video signal based on input image data, a storage unit to store the image data, a detection unit to detect whether or not the number of frames included in one set of image data stored in the storage unit satisfies a predetermined number, and a data creating unit to add, if the number of the frames included in the one set of image data does not satisfy the predetermined number, a new frame to the one set of image data so that the number of the frames included in the one set of image data satisfies the predetermined number, and to input, to the signal output unit, the one set of image data to which the new frame has been added.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of Application PCT/JP2007/067049, filed on Aug.31, 2007, now pending, the contents of which are herein whollyincorporated by reference.

FIELD

The embodiment relates to a signal output device and a signal outputmethod.

BACKGROUND

As a frame rate conversion method, there is a method of adding a framebetween adjacent frames (see Patent document 1). Further, forinterpolation of a video frame, there is a 2-3 pulldown scheme forconverting a 24-frame video of a video film into an interlaced signalexhibiting 60 fields per second. Then, in order to smooth the motion ofan image, there is a method of determining a movement amount from apixel difference and applying the movement amount to the interpolationaccording to the 2-3 pulldown scheme (see Patent document 2).

-   [Patent document 1] Japanese Laid-open Patent Publication No.    2005-124201-   [Patent document 2] Japanese Laid-open Patent Publication No.    2006-165602

SUMMARY

Up to now, by using a personal computer to which a tuner and an antennacapable of receiving a one-segment broadcast (1seg broadcast) areconnected, it is possible to view the 1seg broadcast. In this case,video frames transmitted from a broadcasting station are displayed asthey are.

The 1seg broadcast represents a broadcast for portable/mobile unitswhich is provided by using one segment of 13 segments that are obtainedby dividing a band (6 MHz) per channel of a digital terrestrialtelevision broadcast. Provided by the 1seg broadcast are not onlytelevision programs but also contents including text data and stillimage data.

In the 1seg broadcast, H.264/AVC (level 1.2, 320×240 or 320×180, minimumframe interval 1/15 seconds) is used as a compression coding scheme formoving image data. Therefore, the video is displayed at maximum 15frames/second, and this value is a maximum value. A video format ofvideo data (image data) transmitted from the broadcasting stationdepends on the television program at the broadcasting station. For thatreason, there is a case where the video data is broadcast from thebroadcasting station at 12 frames/second.

There is a difference in quality of an appearance of the displayed videobetween the case where the video data is broadcast at 15 frames/secondand the case where the video data is broadcast at 12 frames/second. Forthat reason, when the channel is switched over, the quality of theappearance may differ between the video before the switching and thevideo after the switching. Further, there may be a difference betweenthe quality of the appearances of the videos broadcast from even thesame broadcasting station.

A signal output device according to one aspect of the embodimentincludes: the embodiment provides a signal output device, including: asignal output unit to output a video signal based on input image data; astorage unit to store the image data; a detection unit to detect whetheror not a number of frames included in one set of image data stored inthe storage unit satisfies a predetermined number; and a data creatingunit to add, if the number of the frames included in the one set ofimage data does not satisfy the predetermined number, a new frame to theone set of image data so that the number of the frames included in theone set of image data satisfies the predetermined number, and to input,to the signal output unit, the one set of image data to which the newframe has been added.

The object and advantages of the embodiment will be realized andattained by means of the elements and combinations particularly pointedout in the claims. It is to be understood that both the foregoinggeneral description and the following detailed description are exemplaryand explanatory and are not restrictive of the embodiment, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a hardware configuration diagram of a personal computeraccording to an embodiment.

FIG. 2 is a functional configuration diagram of the personal computeraccording to the embodiment.

FIG. 3 is an explanatory diagram of inter-frame prediction processing ofH.264/AVC.

FIG. 4 is a diagram illustrating a signal output processing according tothe embodiment.

FIG. 5 is a diagram illustrating a frame interpolation processingaccording to the embodiment.

FIG. 6 is an explanatory diagram of a GOP according to the embodiment.

FIG. 7 is a diagram illustrating an example of the frame interpolationprocessing according to the embodiment.

FIG. 8 is an explanatory diagram of the GOP according to the embodiment.

FIG. 9 is an explanatory diagram of bi-prediction processing ofH.264/AVC.

FIG. 10 is an explanatory diagram of the GOP according to theembodiment.

FIG. 11 is an explanatory diagram of the GOP according to theembodiment.

FIG. 12 is an explanatory diagram of the GOP according to theembodiment.

FIG. 13 is an explanatory diagram of bi-directional prediction ofH.264/AVC.

DESCRIPTION OF EMBODIMENTS

According to the embodiment, a new frame is interpolated so that thenumber of frames included in one set of image data satisfies thepredetermined number. Then, the video signal is output based on the oneset of image data to which the new frame has been added, thereby makingit possible to output such a video signal as to prevent the viewer fromfeeling uncomfortable. That is, by interpolating a new frame into oneset of image data, it becomes possible to output the video signalmaintaining constant quality.

Further, in the signal output device, the data creating unit may divideeach of the frames into a plurality of local regions, calculate movementamount of each of the local regions within the continuous frames, detect2 frames exhibiting the largest movement amount of the local region, andadd the new frame between the 2 frames.

By the data creating unit dividing each of the frames included in oneset of image data into the plurality of local regions, it becomespossible to calculate the movement amount of the local region betweenthe continuous frames. Then, by the data creating unit detecting the 2frames exhibiting the largest movement amount of the local region, itbecomes possible to add a new frame to a video portion that causes theviewer to feel uncomfortable.

Further, in the signal output device, the new frame may be created basedon one frame of the 2 frames and the frame that is different from the 2frames and is adjacent to the one frame. The expression “one frame ofthe 2 frames and the frame that is different from the 2 frames and isadjacent to the one frame” represents the continuous frames. Byreferencing the continuous frames, a new frame can be interpolated intoone set of image data having continuous frames that are missing, whichmakes it possible to provide the video maintaining constant quality.

Further, in the signal output device, the new frame may be created basedon the movement amount and a movement direction between the local regionwithin one frame of the 2 frames and the local region within the framethat is different from the 2 frames and is adjacent to the one frame.The expression “one frame of the 2 frames and the frame that isdifferent from the 2 frames and is adjacent to the one frame” representsthe continuous frames. It is possible to interpolate a new frame intoone set of image data having continuous frames that are missing based onthe movement amount and the movement direction of the local regionwithin the continuous frames, which makes it possible to provide thevideo maintaining constant quality.

Further, in the signal output device, it is preferred that the imagedata includes a moving image; and the frame included in the one set ofimage data be set as a minimum unit structure that forms the movingimage.

Further, the embodiment may provide a method of causing a computer orother such device, machine, or the like to execute any one of theabove-mentioned processing. Further, the embodiment may provide aprogram for causing a computer or other such device, machine, or thelike to execute any one of the above-mentioned processing. Further, theembodiment may provide a computer-readable recording medium having sucha program recorded thereon.

Hereinafter, with reference to the drawings, an information equipmentprovided with an signal output device according to the embodiment isdescribed as a personal computer having a function of allowing viewingof a 1seg broadcast.

A configuration of the embodiment described below is a mere example.

The personal computer according to the embodiment is a personal computerthat includes a tuner for receiving a 1seg broadcast and decoder means,and allows viewing of a 1seg broadcast by displaying a video based onthe video signal obtained by decoding on a display device (display) andreproducing an audio based on an audio signal obtained by decoding.

In the 1seg broadcast, due to a difference in the broadcast program orthe broadcasting station, there is a case where video data (image data)is broadcast at 15 frames/second or a case where the video data isbroadcast at 12 frames/second. In comparison with the case where videodata is broadcast at 15 frames/second, in the case where the video datais broadcast at 12 frames/second, the video data is received in a statein which 3 frames are missing.

Therefore, the embodiment allows a video maintaining constant quality tobe displayed by adding dummy frames for the 3 missing frames even in thecase where video data is broadcast at 12 frames/second.

FIG. 1 is a hardware configuration diagram of a personal computer 1according to the embodiment. As illustrated in FIG. 1, the personalcomputer 1 includes a CPU 2 that executes a computer program to controlthe personal computer 1, a memory 3 that stores the computer programexecuted by the CPU 2 and data processed by the CPU 2, an interface 4that connects the CPU 2 to each kinds of devices, and the devicesconnected through the interface 4 including a broadcast receiving device5, a communication device 6, a hard disk drive unit 7, a portable mediadrive unit 8, an input device 9, and a display device 10.

The memory 3 stores data executed by the CPU 2 and program processed bythe CPU 2. The memory 3 includes a volatile random access memory (RAM)and a nonvolatile read only memory (ROM). The ROM includes a rewritablesemiconductor memory such as a flash memory, an erasable programmableread-only memory (EPROM), and an electrically erasable programmableread-only memory (EEPROM).

The interface 4 may be any one of a serial interface such as universalserial bus (USB), and a parallel interface such as peripheral componentinterconnect (PCI), industry standard architecture (ISA), extended ISA(EISA), AT Attachment (ATA), integrated drive electronics (IDE),IEEE1394, and small computer system interface (SCSI). Note that the CPU2 is connected to each of the devices by the interface 4, but the CPU 2may be connected to each of the devices by a different interface.Further, a plurality of interfaces may be bridge-connected.

The broadcast receiving device 5 includes an antenna, a tuner, and ademodulator, and is controlled by the CPU 2 that executes a devicedriver. The broadcast receiving device 5 uses the antenna to receive abroadcast wave, and uses the tuner to select a channel. Then, thebroadcast receiving device 5 performs an orthogonal frequency divisionmultiplexing (OFDM) demodulation processing based on the broadcast waveon the channel by using the demodulator and a creation processing(decoding processing) for compressed moving image data stream (TS data).The created TS data is output via a bus. The TS data is temporarilystored in the memory 3. Then, the TS data stored in the memory 3 isconverted into a video signal, and output to the display device 10.

The communication device 6 is an interface to a broadband network.Examples of the broadband network include wired networks such as a localarea network (LAN), a cable television network, an x digital subscriberline (xDSL), an ADSL, and an optical network and networks allowingwireless access such as a wireless LAN and a fixed wireless access(FWA). The communication device 6 acquires, for example, a computerprogram installed on the hard disk drive unit 7, an electronic programguide for a television broadcast from a server on the network, and thelike. Those broadband networks can be generally connected to theInternet.

The hard disk drive unit 7 stores a program to be loaded in the memory3. Further, the hard disk drive unit 7 stores data to be processed bythe CPU 2.

The portable media drive unit 8 is, for example, a drive unit for acompact disc (CD), a digital versatile disk (DVD), an HD-DVD, a Blu-raydisc, and the like. Further, the portable media drive unit 8 may be aninput/output device for a card medium having a nonvolatile memory suchas a flash memory. A medium driven by the portable media drive unit 8retains the computer program installed on the hard disk drive unit 7,input data, and the like. Examples of the input device 9 include akeyboard, a mouse, a pointing device, and a wireless remote control.

The display device 10 displays a video based on a video signal. Thevideo is displayed on the display device 10 to thereby allow the user toview the television broadcast. Examples of the display device 10 includea liquid crystal display device, a plasma display panel, a cathode raytube (CRT), and an electroluminescence panel. Further, the displaydevice 10 is attached with a speaker; which outputs an audio based onthe audio signal.

The information equipment provided with the signal output deviceaccording to the embodiment can be configured as the personal computer 1as described above. However, the information equipment provided with thesignal output device according to the embodiment is not limited to thepersonal computer 1, and may be another device having a functionequivalent thereto such as a television receiver. Further, theinformation equipment can be realized by a tuner for receiving atelevision broadcast, a set-top box, a mobile telephone with atelevision broadcast receiving function, a mobile information terminal(PDA), a game machine, an in-vehicle device with a television broadcastreceiving function, and the like.

FIG. 2 is a functional configuration diagram of the personal computer 1according to the embodiment. The personal computer 1 includes anoperation unit 20 that operates the personal computer in response to auser's operation, a sensing unit 21 that senses an operation performedon the operation unit 20, a broadcast receiving unit 22 that receives abroadcast wave (television broadcast) and decodes data on the receivedbroadcast wave into TS data, a detection unit 23 that detects whether ornot the TS data output from the broadcast receiving unit 22 needsinterpolation, a storage unit 24 that temporarily stores the TS dataoutput from the broadcast receiving unit 22, a data creating unit 25that creates new TS data based on the TS data stored in the storage unit24, a signal output unit 26 that converts the TS data output from thestorage unit 24 and the TS data output from the data creating unit 25into a video signal and inputs the video signal to a display unit 27,and the display unit 27 that displays a video based on the input videosignal.

The operation unit 20, the sensor unit 21, the broadcast receiving unit22, the detection unit 23, the storage unit 24, the data creating unit25, the signal output unit 26 and the display unit 27 can be realized bya computer including the CPU 2 and the memory 3, the respective devices,programs executed on the computers, and the like.

The operation unit 20 is operated in a case where an input is receivedfrom the user and a predetermined command and necessary data are inputand other such case.

The sensing unit 21 senses an operation performed on the operation unit20 (for example, a start operation for viewing a broadcast program or aswitch operation for a receiving channel). The sensing unit 21 may beconfigured as a computer program executed on the CPU 2. Further,dedicated hardware may be provided as the sensing unit 21.

The broadcast receiving unit 22 receives the broadcast wave through theantenna, and outputs the data stream (for example, TS data) based on thereceived broadcast wave. The broadcast receiving unit 22 may beconfigured as a computer program executed on the broadcast receivingdevice 5 or the CPU 2.

The detection unit 23 monitors the TS data output from the broadcastreceiving unit 22, and detects which of 12 frames and 15 frames a GOP ofthe TS data has. In the H.264/AVC, as illustrated in FIG. 3, inter-frameprediction processing is performed within 3 or less reference pictures(100, 101, and 102), and a predictive picture (P picture) 103 iscreated. In the embodiment, the P picture 103 illustrated in FIG. 3 iscalled “picture” or “frame”. In the embodiment, the TS data that isvideo data may be a moving image, and a frame included in the GOP of theTS data may be set as a minimum unit structure that forms a movingimage. Further, a group of a set of frames separated by an IDR pictureis called “group of pictures (GOP)”. In the embodiment, there is a casewhere the GOP has 12 frames and a case where the GOP has 15 frames.Further, in the embodiment, a reproduction duration of one GOP is onesecond. The detection unit 23 may be configured as a computer programexecuted on the CPU 2.

The storage unit 24 temporarily stores the input data. The storage unit24 receives an input of the TS data output from the broadcast receivingunit 22, and stores the TS data that is 3 seconds long in terms of thereproduction duration. The TS data stored in the storage unit 24 isinput to the data creating unit 25 or the signal output unit 26. Thestorage unit 24 is configured as a recording medium controlled by thecomputer program executed on the CPU 2, the recording medium including avolatile memory, a nonvolatile memory such as a flash memory, a harddisk, and a portable medium. Further, the storage unit 24 may beconfigured as a memory dedicated to store the input data.

The data creating unit 25 counts the number of frames included in theGOP separated by the IDR picture to thereby judge which of 12 frames and15 frames the GOP of the TS data stored in the storage unit 24 has. Ifthe GOP of the TS data stored in the storage unit 24 has 12 frames, thedata creating unit 25 adds 3 frames to the GOP of the TS data (frameinterpolation), and outputs the TS data having 15 frames of the GOP tothe signal output unit 26. The data creating unit 25 may be configuredas a computer program executed on the CPU 2.

The signal output unit 26 includes an interface to the display unit 27,and controls the TS data to be output to the display unit 27. That is,the signal output unit 26 converts the TS data input from the storageunit 24 or the data creating unit 25 into the video signal that can bedisplayed by the display unit 27 or the audio signal, and outputs thevideo signal or the audio signal to the display unit 27. Further, thesignal output unit 26 receives an input of the TS data delayed by 3seconds after a time when the broadcast wave is received by thebroadcast receiving unit 22. The signal output unit 26 may be configuredas a computer program executed on the CPU 2. Further, the signal outputunit 26 may be configured as a processor dedicated to output the videosignal and the audio signal.

Upon reception of the input of the video signal and the audio signaloutput from the signal output unit 26, the display unit 27 displays thevideo and reproduces the audio. Further, the display unit 27 receives aninput of the video signal and the audio signal delayed by 3 secondsafter a time when the broadcast wave is received by the broadcastreceiving unit 22.

In the embodiment, an amount of the stored TS data corresponds to 3seconds in terms of the time required for reproduction thereof as themoving image or the audio. For example, the moving image data has 12frames or 15 frames per second in the 1seg broadcast, and hence themoving image data having approximately 36 frames to 45 frames is stored.The storage amount may preferably be set to be as large as possible, butis set to 3 seconds in the embodiment in consideration of a size of thestorage area that can be secured on the personal computer 1. However,the storage amount may preferably be set to an optimum valueappropriately for each embodiment. For example, a capacity of a mainmemory that can be secured may be increased by terminating a residentapplication or an unnecessary application or by not using a part of themain memory as a video memory (by providing a separate video memory),thereby increasing the storage amount.

Further, the personal computer 1 according to the embodiment performs anoutput of the TS data delayed by 3 seconds. In other words, in a casewhere the 1seg broadcast is viewed on the personal computer 1 accordingto the embodiment, the video and the audio are output with a delay byapproximately 3 seconds in comparison with a case of viewing on anothergeneral 1seg broadcast viewing device. By performing the delayed output,even if the video data having a small number of frames is received,instead of outputting the video signal having a small number of framesas they are, it becomes possible to interpolate a video corresponding toa portion of the lacking number of frames by reproducing the stored datathat has not been output with a delay.

<Processing Flow>

FIG. 4 and FIG. 5 illustrate a processing flow for the personal computer1. FIG. 4 is a flowchart illustrating a signal output processingaccording to the embodiment. FIG. 5 is a flowchart illustrating a frameinterpolation processing according to the embodiment.

<Signal Output Processing>

Description is made of the signal output processing of FIG. 4. Thesignal output processing according to the embodiment is executed by thesensing unit 21 detecting a television viewing start operation performedon the operation unit 20 and by a signal of an instruction to start thesignal output processing being output from the sensing unit 21 to thesignal output unit 26.

First, the TS data is output from the broadcast receiving unit 22 (StepS101). Subsequently, the detection unit 23 that has received the TS dataoutput from the broadcast receiving unit 22 judges whether or not theGOP of the TS data has any one of 12 frames and 15 frames (Step S102).

If the GOP of the TS data has none of 12 frames and 15 frames (NO in theprocessing of Step S102), the detection unit 23 outputs a signalindicating impossible video display to the signal output unit 26 (StepS103). The signal output unit 26 to which the signal indicatingimpossible video display has been input outputs the video signalincluding a message indicating that normal display cannot be performedto the display unit 27. The display unit 27 to which the video signalincluding the message indicating that normal display cannot be performedhas been input displays the message indicating that normal displaycannot be performed. For example, the display unit 27 performs displayof “No signal”. This allows a viewer to grasp a situation in which theviewing is made impossible due to some factor. If the detection unit 23outputs the signal indicating impossible video display to the signaloutput unit 26, the procedure advances to the processing of Step S101.

Meanwhile, if the GOP of the TS data has one of 12 frames and 15 frames(YES in the processing of Step S102), the TS data is stored into thestorage unit 24 (Step S104). If the TS data corresponding to 3 secondsis stored into the storage unit 24, the procedure advances to theprocessing of Step S105.

Subsequently, the data creating unit 25 judges whether or not the GOP ofthe TS data stored in the storage unit 24 has 15 frames (Step S105).That is, the data creating unit 25 judges whether or not the number offrames included in the GOP stored in the storage unit 24 is 15.

If the GOP of the TS data has 15 frames (YES in the processing of StepS105), the TS data is input from the storage unit 24 to the signaloutput unit 26. Then, by the signal output unit 26, the TS data isconverted into a video signal and input to the display unit 27. Thedisplay unit 27 displays the video according to the video signal inputfrom the signal output unit 26 (Step S106).

Meanwhile, if the GOP of the TS data does not have 15 frames (NO in theprocessing of Step S105), the data creating unit 25 adds new frames tothereby create the TS data in which the number of frames included in theGOP is 15 frames (Step S107). The data creating unit 25 outputs the TSdata in which the number of frames included in the GOP is 15 frames tothe signal output unit 26. The TS data input to the signal output unit26 is converted into the video signal and input to the display unit 27.The display unit 27 displays the video according to the video signalinput from the signal output unit 26 (Step S106). If the TS datacorresponding to 3 seconds stored in the storage unit 24 is processed,the procedure advances to the processing of Step S101.

<Frame Interpolation Processing>

Next, description is made of a new-frame addition processing (frameinterpolation processing) performed by the data creating unit 25 in StepS107 of FIG. 4. FIG. 5 is a flowchart illustrating the frameinterpolation processing performed by the data creating unit 25.

The data creating unit 25 divides the TS data in which the number offrames included in the GOP is not 15 frames among the TS data which isstored in the storage unit 24 (Step S201). That is, the data creatingunit 25 divides the TS data in which the number of frames included inthe GOP is 12 frames among the TS data which is stored in the storageunit 24. In this case, the data creating unit 25 divides 12 frames into3 frame groups to thereby create 3 suites of 4-frame group.

FIG. 6 is an explanatory diagram of the GOP in a case where 12 framesare divided into the 3 frame groups. A frame P01 is a frame thatdisplays the past video temporally preceding a frame P02. By beingseparated by the IDR picture, 12 frames from the frame P01 to the frameP12 form the GOP.

In the embodiment, an example of creating 3 suites of 4-frame group isillustrated, but the embodiment is not limited thereto, and the numberof frames included in the frame group may be appropriately changed. Forexample, four suites of 3-frame group, or 2 suites of 6-frame group maybe created. Further, the TS data corresponding to 3 seconds is stored inthe storage unit 24, and hence the suite of frame group may be createdfrom a frame included in a different GOP. For example, the suite offrame group may be created from the frame P01, the frame P02, and theframe P03 of FIG. 6 and the frame included in the GOP of the TS datawhich displays the past video temporally preceding the GOP illustratedin FIG. 6.

Next, returning to the description of FIG. 5, the data creating unit 25calculates a movement amount V of a target block by referencingrespective frames stored in the storage unit 24 (Step S202). Here, withreference to FIG. 7, the movement amount V of the target block isdescribed. The frame P05, the frame P06, the frame P07, and the frameP08 of FIG. 7 represent the frames (TS data) stored in the storage unit24. Here, the frames stored in the storage unit 24 are output from thestorage unit 24 in order of the frame P05, the frame P06, the frame P07,and the frame P08.

In the embodiment, the frame is divided into macro blocks (correspondingto “local regions”), and the movement amounts of the macro blocks arecalculated. In the frame P05, the frame P06, the frame P07, and theframe P08 of FIG. 7, the target blocks (macro blocks) are denoted byreference symbols C and D.

The data creating unit 25 references the respective frames stored in thestorage unit 24 to detect a movement of the target block by detecting afluctuation amount of a color difference signal in the target block.Then, the data creating unit 25 calculates the movement amount V of thetarget block from which the movement has been detected. That is, theframes are continuously stored in the storage unit 24, and hence thedata creating unit 25 compares the continuous frames with each other,and calculates the movement amount V of the target block common to the 2frames.

If the frame P07 and the frame P08 illustrated in FIG. 7 are comparedwith each other, only the target block D exhibits the fluctuation amountof the color difference signal, and hence the movement of the targetblock D is detected. Further, if the frame P07 and the frame P08illustrated in FIG. 7 are compared with each other, the target block Cdoes not exhibit the fluctuation amount of the color difference signal,and hence the movement of the target block C is not detected.

Note that if the movements of a plurality of target blocks are detectedin the processing of Step S202 in FIG. 5, the data creating unit 25 maycalculate the movement amount V of the target block with regard to thetarget block exhibiting the largest movement amount among the detectedtarget blocks. This is because the viewer's attention is likely to befocused on a portion exhibiting a large change within the video.Further, if the movements of a plurality of target blocks are detectedin the processing of Step S202, the data creating unit 25 may calculatea mean value of the movement amounts of the detected plurality of targetblocks as the movement amount V of the target block.

Returning to the description of FIG. 5, the data creating unit 25references the respective frames stored in the storage unit 24 to detect2 frames exhibiting the largest movement amount V of the target block(Step S203). Here, detailed description is made of a processing fordetecting the 2 frames exhibiting the largest movement amount V of thetarget block. FIG. 8 is an explanatory diagram of the GOP. FIG. 8illustrates one GOP, in which 12 frames are divided into a frame group200, a frame group 201, and a frame group 202. If the 2 framesexhibiting the largest movement amount V of the target block aredetected from the frame group 201, the data creating unit 25 referencesthe frame P04, the frame P05, the frame P06, the frame P07, the frameP08, and the frame P09. Therefore, the data creating unit 25 referencesthe frames within the frame group and the frames continuous to theframes within the frame group (in FIG. 8, the frame P04 and the frameP09) to thereby detect the 2 frames exhibiting the largest movementamount V of the target block.

Returning to the description of FIG. 5, the data creating unit 25decides a position in which a new frame is to be inserted (Step S204).Specifically, the data creating unit 25 decides to insert a new framebetween the 2 frames detected in the processing of Step S203.

Subsequently, the data creating unit 25 references 2 any frames storedin the storage unit 24 to calculate a movement vector (movement amountand movement direction) of the target block (Step S205). For example,one of the 2 frames detected in the processing of Step S203 and theframe continuous to the one frame may be referenced to calculate themovement vector of the target block. In FIG. 7, the frame P07 and theframe P08 are referenced to calculate the movement vectors of the targetblock C and the target block D. Further, the frame P05 and the frame P06may be referenced to calculate the movement vectors of the target blockC and the target block D.

Returning to the description of FIG. 5, the data creating unit 25estimates the position of the target block from the calculated movementvector and creates a new frame (Step S206). In FIG. 7, the positions ofthe target block C and the target block D are estimated from themovement vectors of the target block C and the target block D, and a newframe PB is created.

Here, with reference to FIG. 9, description is made of creation of thenew frame by bi-prediction processing of H.264/AVC. In the bi-predictionprocessing of H.264/AVC, 2 any frames are referenced to create a newframe. In FIG. 9, the target block F within the frame P201 and thetarget block F within the frame P202 are referenced to create the targetblock F within a new frame PC. The frame P201 and the frame P202represent a video displayed temporally after the new frame PC. The newframe PB illustrated in FIG. 7 is created by the above-mentionedprocessing illustrated in FIG. 9.

Returning to the description of FIG. 5, the data creating unit 25inserts the newly-created frame in the position decided in theprocessing of Step S204 (Step S207). The data creating unit 25repeatedly performs the processing from Step S202 to Step S207 on eachof the 3 frame groups obtained by the dividing, and the frameinterpolation processing is brought to an end.

Note that if a new frame has already been inserted in the processing ofStep S204, the data creating unit 25 may decide a position in which anew frame is to be inserted by excluding the position in which the newframe has already been inserted. FIG. 10 is an explanatory diagram ofthe GOP. FIG. 10 illustrates one GOP, in which 12 frames are dividedinto the frame group 200, the frame group 201, and the frame group 202.For example, if the position in which a new frame is to be added to theframe group 200 of FIG. 10 is a position A of FIG. 10, the position A ofFIG. 10 may be excluded as the position in which a new frame is to beadded to the frame group 201 of FIG. 10. Note that positions B, C, D,and E of FIG. 10 indicate positions in which a new frame can be added.

In addition, for example, if the position in which a new frame is addedto the frame group 200 of FIG. 10 is the position A of FIG. 10, when anew frame is added to the frame group 201 of FIG. 10, reference may bemade to the new frame added to the frame group 200. FIG. 11 illustratesan explanatory diagram of the GOP in a case where a new frame PD isadded to the frame group 200. In this case, when a new frame is added tothe frame group 201 of FIG. 11, reference may be made to the new framePD, the frame P05, the frame P06, the frame P07, the frame P08, and theframe P09. With such a configuration, it is also possible to insert anew frame PE between the new frame PD and the frame P05. The datacreating unit 25 may store the newly-created frame PD in the storageunit 24 and reference the new frame PD in a case of creating the newframe PE.

FIG. 12 is an explanatory diagram of the GOP in a case where new framesare added to convert the number of frames included in the GOP from 12frames to 15 frames. A new frame PA is added to the frame group 300, thenew frame PB is added to the frame group 301, and the new frame PC isadded to the frame group 302. Accordingly, in the embodiment, new framesare added, the TS data in which the number of frames included in the GOPis changed to 15 frames is output, and the video is displayed based onthe 15-frame video signal.

According to the embodiment, when the video data having a small numberof frames is received, by adding frames, it becomes possible to displaysuch a video as to prevent the viewer from feeling uncomfortable.

Here, description is made of a case of creating a new frame byreferencing both 2 frames exhibiting the largest movement amount of thetarget block. In bi-directional prediction processing of H.264/AVC, in acase of adding a new frame, 2 frames sandwiching the new frame to beadded are referenced to create the new frame. Then, the new frame isinserted between the referenced 2 frames. However, the frame to bereferenced may be missing, which may inhibit the new frame to be createdwith accuracy. This occurs in a case where, when the 12-frame GOP isreceived, 3 frames are missing and the missing 3 frames are continuousframes.

FIG. 13 is an explanatory diagram of frames to be referenced by thebi-directional prediction processing of H.264/AVC. FIG. 13 illustrates acase where the GOP of a source video has 15 frames but the GOP of thereceived TS data has 12 frames. The frames from the frame P01 to theframe P12 represent frames included in the GOP of the received TS data,and a frame PX, a frame PY, and a frame PZ represent missing frames fromthe GOP of the source video.

As illustrated in FIG. 13, the frame PX and the frame PY representcontinuous frames within the GOP of the source video. A frame PTrepresents a frame newly created by the bi-directional predictionprocessing. In a case where the new frame PT is created by thebi-directional prediction processing, frames to be referenced are theframe P02 and the frame PY or the frame PX and the frame P03. However,the frame PY is missing, and hence the new frame PT cannot be created byreferencing the frame P02 and the frame PY. Further, the frame PX ismissing, and hence the new frame PT cannot be created by referencing theframe PX and the frame P03.

That is, if there are continuous frames that are missing within the GOPof the received TS data, the movement amount of the target block betweenframes (in FIG. 13, the frame P02 and the frame P03) adjacent to thecontinuous frames that are missing is too large to estimate the positionof the target block within the new frame by the bi-directionalprediction processing.

In the embodiment, the new frame is created by referencing one of the 2frames exhibiting the largest movement amount of the target block andthe frame different from the 2 frames exhibiting the largest movementamount of the target block. The different frame is a frame adjacent toone of the 2 frames exhibiting the largest movement amount of the targetblock.

Therefore, according to the embodiment, even if the movement amount ofthe target block is too large, that is, if the movement amount of thetarget block exceeds an allowable amount that can be referenced by thebi-directional prediction processing, it is possible to estimate theposition of the target block within the new frame. For that reason, evenif the movement amount of the target block is too large, it is possibleto create the new frame.

Further, in the embodiment, the new frame is created by referencing notboth but one of the 2 frames exhibiting the largest movement amount ofthe target block. Accordingly, according to the embodiment, it ispossible to create the new frame even if continuous frames are missing.

<Computer Readable Recording Medium>

It is possible to record a program which causes a computer to implementany of the functions described above on a computer readable recordingmedium. By causing the computer to read in the program from therecording medium and execute it, the function thereof can be provided.The computer readable recording medium mentioned herein indicates arecording medium which stores information such as data and a program byan electric, magnetic, optical, mechanical, or chemical operation andallows the stored information to be read from the computer. Of suchrecording media, those detachable from the computer include, e.g., aflexible disk, a magneto-optical disk, a CD-ROM, a CD-R/W, a DVD, a DAT,an 8-mm tape, and a memory card. Of such recording media, those fixed tothe computer include a hard disk and a ROM.

All examples and conditional language recited herein are intended forpedagogical purposes to aid the reader in understanding the inventionand the concepts contributed by the inventor to furthering the art, andare to be construed as being without limitation to such specificallyrecited examples and conditions, nor does the organization of suchexamples in the specification relate to a showing of the superiority andinferiority of the invention. Although the embodiment of the presentinventions have been described in detail, it should be understood thatthe various changes, substitutions, and alterations could be made heretowithout departing from the spirit and scope of the invention.

What is claimed is:
 1. A signal output device, comprising: a signaloutput unit to output a video signal based on input image data; astorage unit to store the image data; a detection unit to detect whetheror not the number of frames included in one set of image data stored inthe storage unit satisfies a predetermined number, wherein the one setof image data is a group of pictures (GOP) separated by IDR; and a datacreating unit to divide, when the number of the frames included in theone set of image data does not satisfy the predetermined number, theframes included in the one set of image data into a plurality of groups,to divide each of the frames into a plurality of local regions, todecide the local region exhibiting the largest movement amount among theplurality of local regions for each of the groups, to detect 2 framesexhibiting the largest movement amount of the decided local region foreach of the groups, and to add a new frame between the 2 frames withineach of the groups, and to input, to the signal output unit, the one setof image data to which the new frame has been added.
 2. The signaloutput device according to claim 1, wherein the new frame is createdbased on one frame of the 2 frames and the frame that is different fromthe 2 frames and is adjacent to the one frame.
 3. The signal outputdevice according to claim 1, wherein the new frame is created based onthe movement amount and a movement direction between the local regionwithin one frame of the 2 frames and the local region within the framethat is different from the 2 frames and is adjacent to the one frame. 4.The signal output device according to claim 1, wherein: the image datacomprises a moving image; and the frame included in the one set of imagedata is set as a minimum unit structure that forms the moving image. 5.A signal output method of causing a computer to execute: detectingwhether or not the number of frames included in one set of image datastored in a storage unit that stores the image data satisfies apredetermined number, wherein the one set of image data is a group ofpictures (GOP) separated by IDR; dividing, when the number of the framesincluded in the one set of image data does not satisfy the predeterminednumber, the frames included in the one set of image data into aplurality of groups; dividing each of the frames into a plurality oflocal regions; deciding the local region exhibiting the largest movementamount among the plurality of local regions for each of the groups;detecting 2 frames exhibiting the largest movement amount of the decidedlocal region for each of the groups; adding a new frame between the 2frames within each of the groups; and outputting the video signal basedon the one set of image data to which the new frame has been added. 6.The signal output method according to claim 5, wherein the new frame iscreated based on one frame of the 2 frames and the frame that isdifferent from the 2 frames and is adjacent to the one frame.
 7. Thesignal output method according to claim 5, wherein the new frame iscreated based on the movement amount and a movement direction betweenthe local region within one frame of the 2 frames and the local regionwithin the frame that is different from the 2 frames and is adjacent tothe one frame.
 8. The signal output method according claim 5, wherein:the image data comprises a moving image; and the frame included in theone set of image data is set as a minimum unit structure that forms themoving image.
 9. A non-transitory computer readable storage mediumstoring a signal output program for causing a computer to execute:detecting whether or not the number of frames included in one set ofimage data stored in a storage unit that stores the image data satisfiesa predetermined number, wherein the one set of image data is a group ofpictures (GOP) separated by IDR; dividing, when the number of the framesincluded in the one set of image data does not satisfy the predeterminednumber, the frames included in the one set of image data into aplurality of groups; dividing each of the frames into a plurality oflocal regions; deciding the local region exhibiting the largest movementamount among the plurality of local regions for each of the groups;detecting 2 frames exhibiting the largest movement amount of the decidedlocal region for each of the groups; adding a new frame between the 2frames within each of the groups; and outputting the video signal basedon the one set of image data to which the new frame has been added. 10.The non-transitory computer readable storage medium storing the signaloutput program according to claim 9, wherein the new frame is createdbased on one frame of the 2 frames and the frame that is different fromthe 2 frames and is adjacent to the one frame.
 11. The non-transitorycomputer readable storage medium storing the signal output programaccording to claim 9, wherein the new frame is created based on themovement amount and a movement direction between the local region withinone frame of the 2 frames and the local region within the frame that isdifferent from the 2 frames and is adjacent to the one frame.
 12. Thenon-transitory computer readable storage medium storing the signaloutput program according to claim 9, wherein: the image data comprises amoving image; and the frame included in the one set of image data is setas a minimum unit structure that forms the moving image.